Dental calculus, or tartar as it is sometimes called, is a deposit which forms on the surfaces of teeth at the gingival margin. Supragingival calculus appears principally in the areas near the orifices of the salivary ducts; e.g., on the lingual surfaces of the lower anterior teeth and on buccal surfaces of the upper first and second molars, and on the distal surfaces of the posterior molars.
Mature calculus consists of an inorganic portion which is largely calcium phosphate arranged in a hydroxyapatite crystal lattice structure similar to bone, enamel, and dentine. An organic portion is also present and consists of desquamated epithelial cells, leukocytes, salivary sediment, food debris, and various types of micro-organisms.
As the mature calculus develops, its appearance becomes visibly white or yellowish in color unless stained or discolored by some extraneous agent. This is undesirable from an aesthetic standpoint. One way to address the problem is with routine dental visits to mechanically remove the calculus deposits. Another solution is through the use of a variety of chemical and biological agents to retard calculus formation or to remove calculus after its formation.
The latter approach to chemically inhibit calculus formation generally involves chelation of calcium ion and/or crystal growth inhibition. This approach prevents the calculus from forming and/or breaks down mature calculus through the removal of calcium. There are a number of chelating agents that are well-known as being effective for this purpose, such as for example, pyrophosphate salts and polyphosphates.
Silica is a commonly used abrasive in oral care compositions. Calcium containing abrasives have also been used in oral compositions (e.g., toothpastes). However, the problem with calcium containing abrasives is that the calcium ions will complex with free pyrophosphate or phosphate ions and other anti-calculus sources in the oral compositions, leading to a potential decrease in anti-calculus efficacy. As a result, calcium containing abrasives, such as for example calcium carbonate, are not preferred abrasives in anti-calculus oral compositions.
Thus, there is a need for an oral composition with improved anti-calculus efficacy. It is desirable that the oral composition provides improved cleaning efficacy.